hypercalcaemia

Question 1

what are the commonest causes of hypercalcaemia?

Answer 1

primary hyperparathyroidism, where the parathyroid gland(s) becomes overactive and secretes excess amounts of parathyroid hormone (PTH).

malignancy also

Question 2

how can you determine the underlying cause for hypercalcaemia?

Answer 2

hallmark of malignancy being the cause is low PTH levels (malignancy is suspected unless proven otherwise),

whereas primary hyperparathyroidism is typically associated with normal or high PTH

Question 3

what cell type are malignant causes of hypercalcaemia usually associated with?

Answer 3

squamous cell epithelial tumours due to the secretion of PTH related peptide (PTH-rP)

Question 4

how advanced does a malignancy have to be to be the cause of hypercalcaemia?

Answer 4

occurs in large or advanced tumours

bony mets not always present

Question 5

other than malignancy, where can hypercalcaemia with low PTH be seen?

Answer 5

in benign granulomatous disease such as TB or sarcoidosis

Question 6

what does hypercalcaemia with non suppressed PTH suggest?

Answer 6

suggests primary hyperPTH until proven otherwise

Question 7

what is the most common cause of primary hyperparathyroidism?

Answer 7

a single parathyroid adenoma

parathyroid hyperplasia in more thane gland may suggest a genetic cause

Question 8

what can a very high serum calcium with a large parathyroid tumour suggest?

Answer 8

parathyroid cancer but this is v rare

may occur rarely in association with jaw tumours (hyperparathyroidism- jaw tumour syndrome)

Question 9

how high does calcium have to consider hypercalcaemia?

Answer 9

> 2.6 mmol/L

Question 10

what are the clinical features of hypercalcaemia?

Answer 10

usually asymptomatic and discovered incidentally

non specific symptoms

• tiredness
• generalised aches and pains

specific symptoms
- polyuria
- polydipsia
due to nephrogenic diabetes insipidus

• abdominal pain
• constipation
• psychiatric symptoms
• kidney stones

STONES, MOANS (DEPRESSION), GROANS (ABDO PAIN)

severe metabolic parathyroid bone disease can have a classical cyst appearance on x ray

Question 11

what will investigations into hypercalcaemia show?

Answer 11

• PTH will be high or non suppressed if primary hyperparathyroidism if the cause
• low phosphate is usually present as PTH causes excretion of phosphate
• High ALP reflects increased bone turnover, common in patients with vit D deficiency
• bone density may be reduced, especially at distal radius
• renal US may show nephrocalcinosis
• sub periosteal erosion of the phalanges may be present in severe disease

Question 12

what is familial hypocalcinuric hypercalcaemia?

Answer 12

a rare condition caused by a genetic defect in the calcium sensing receptor.

causes abnormally high levels of calcium in the blood (hypercalcemia) and low to moderate levels of calcium in urine (hypocalciuric).

distinguished from primary hyperparathyroidism by showing low urine calcium/creatinine ratio

family history of mild hypercalcaemia

need to exclude FHH before unnecessary next exploration

Question 13

how is a parathyroid adenoma localised?

Answer 13

hard if lesion is small

parathyroid US will detect usually

SETAMIBI isotope is often used alongside ultrasound

some centres can use SPECT CT / MRI and 4-D CT.

Question 14

how is hyperparathyroidism treated?

Answer 14

surgery if

• serum calcium is >2.85 mmol/L
• if symptoms debilitating
• if patient is young

parathyroidectomy can be done

medical management where surgery is not desirable or simple observation may be appropriate

Calcimimetic drugs e.g cinacalet are effective at lowering Ca in primary hyperparathyroidism

Question 15

is acute severe hypercalcaemia a medical emergency?

Answer 15

YES

may present with profound dehydration and renal impairment, requires urgent treatment and consideration of the cause